industrial melanism in the peppered moth

The light gray form of the peppered moth (Biston betularia) is inconspicuous on the lichen-covered tree trunk. In contrast, the dark (melanic) morph stands out, leaving it vulnerable to predation by birds. The gradual darkening of the wings of the melanic peppered moth, the result of living in woodlands darkened by industrial pollution, is an example of industrial melanism.

From the experiments of Dr. H.B.D. Kettlewell, University of Oxford; photographs by John S. Haywood